it will appear as a kernel argument readable via /proc/cmdline by programs
running once the system is up.
+The number of kernel parameters is not limited, but the length of the
+complete command line (parameters including spaces etc.) is limited to
+a fixed number of characters. This limit depends on the architecture
+and is between 256 and 4096 characters. It is defined in the file
+./include/asm/setup.h as COMMAND_LINE_SIZE.
+
+
53c7xx= [HW,SCSI] Amiga SCSI controllers
See header of drivers/scsi/53c7xx.c.
See also Documentation/scsi/ncr53c7xx.txt.
acpi_skip_timer_override [HW,ACPI]
Recognize and ignore IRQ0/pin2 Interrupt Override.
For broken nForce2 BIOS resulting in XT-PIC timer.
+ acpi_use_timer_override [HW,ACPI}
+ Use timer override. For some broken Nvidia NF5 boards
+ that require a timer override, but don't have
+ HPET
acpi_dbg_layer= [HW,ACPI]
Format: <int>
autotest [IA64]
- awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
- Format: <io>,<memsize>,<isapnp>
-
aztcd= [HW,CD] Aztech CD268 CDROM driver
Format: <io>,0x79 (?)
clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
[Deprecated]
- Forces specified clocksource (if avaliable) to be used
+ Forces specified clocksource (if available) to be used
when calculating gettimeofday(). If specified
- clocksource is not avalible, it defaults to PIT.
+ clocksource is not available, it defaults to PIT.
Format: { pit | tsc | cyclone | pmtmr }
disable_8254_timer
Default value is 0.
Value can be changed at runtime via /selinux/enforce.
- es1370= [HW,OSS]
- Format: <lineout>[,<micbias>]
- See also header of sound/oss/es1370.c.
-
es1371= [HW,OSS]
Format: <spdif>,[<nomix>,[<amplifier>]]
See also header of sound/oss/es1371.c.
eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
Format: <io>[,<irq>]
+ failslab=
+ fail_page_alloc=
+ fail_make_request=[KNL]
+ General fault injection mechanism.
+ Format: <interval>,<probability>,<space>,<times>
+ See also /Documentation/fault-injection/.
+
fd_mcs= [HW,SCSI]
See header of drivers/scsi/fd_mcs.c.
floppy= [HW]
See Documentation/floppy.txt.
- ftape= [HW] Floppy Tape subsystem debugging options.
- See Documentation/ftape.txt.
-
gamecon.map[2|3]=
[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
support via parallel port (up to 5 devices per port)
gscd= [HW,CD]
Format: <io>
- gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
-
- gus= [HW,OSS]
- Format: <io>,<irq>,<dma>,<dma16>
-
gvp11= [HW,SCSI]
hashdist= [KNL,NUMA] Large hashes allocated during boot
hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
- noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
-
i8042.direct [HW] Put keyboard port into non-translated mode
- i8042.dumbkbd [HW] Pretend that controlled can only read data from
- keyboard and can not control its state
+ i8042.dumbkbd [HW] Pretend that controller can only read data from
+ keyboard and cannot control its state
(Don't attempt to blink the leds)
i8042.noaux [HW] Don't check for auxiliary (== mouse) port
i8042.nokbd [HW] Don't check/create keyboard port
idle= [HW]
Format: idle=poll or idle=halt
+ ignore_loglevel [KNL]
+ Ignore loglevel setting - this will print /all/
+ kernel messages to the console. Useful for debugging.
+
ihash_entries= [KNL]
Set number of hash buckets for inode cache.
Format: <RDP>,<reset>,<pci_scan>,<verbosity>
isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
- Format: <cpu number>,...,<cpu number>
+ Format:
+ <cpu number>,...,<cpu number>
+ or
+ <cpu number>-<cpu number> (must be a positive range in ascending order)
+ or a mixture
+ <cpu number>,...,<cpu number>-<cpu number>
This option can be used to specify one or more CPUs
to isolate from the general SMP balancing and scheduling
algorithms. The only way to move a process onto or off
(machvec) in a generic kernel.
Example: machvec=hpzx1_swiotlb
- mad16= [HW,OSS] Format:
- <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
-
- maui= [HW,OSS]
- Format: <io>,<irq>
-
max_loop= [LOOP] Maximum number of loopback devices that can
be mounted
Format: <1-256>
emulation library even if a 387 maths coprocessor
is present.
+ noaliencache [MM, NUMA] Disables the allcoation of alien caches in
+ the slab allocator. Saves per-node memory, but will
+ impact performance on real NUMA hardware.
+
noalign [KNL,ARM]
noapic [SMP,APIC] Tells the kernel to not make use of any
IOAPICs that may be present in the system.
- apic [APIC,i386] Override default heuristics to enable/disable the local
- APIC by CONFIG_X86_APIC_AUTO. When this option is set the kernel
- will try to use the local APIC.
-
noasync [HW,M68K] Disables async and sync negotiation for
all devices.
in certain environments such as networked servers or
real-time systems.
+ noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
+
noirqdebug [IA-32] Disables the code which attempts to detect and
disable unhandled interrupt sources.
+ no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
+ broken timer IRQ sources.
+
noisapnp [ISAPNP] Disables ISA PnP code.
noinitrd [RAM] Tells the kernel not to load any configured
opl3= [HW,OSS]
Format: <io>
- opl3sa= [HW,OSS]
- Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
-
opl3sa2= [HW,OSS] Format:
<io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
Mechanism 1.
conf2 [IA-32] Force use of PCI Configuration
Mechanism 2.
+ mmconf [IA-32,X86_64] Enable use of MMCONFIG for PCI
+ Configuration
nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
Configuration
+ msi [MSI] If the PCI_MSI kernel config parameter is
+ enabled, this kernel boot option can be used to
+ enable the use of MSI interrupts system-wide.
nomsi [MSI] If the PCI_MSI kernel config parameter is
enabled, this kernel boot option can be used to
disable the use of MSI interrupts system-wide.
bootloader. This is currently used on
IXP2000 systems where the bus has to be
configured a certain way for adjunct CPUs.
+ noearly [X86] Don't do any early type 1 scanning.
+ This might help on some broken boards which
+ machine check when some devices' config space
+ is read. But various workarounds are disabled
+ and some IOMMU drivers will not work.
+ bfsort Sort PCI devices into breadth-first order.
+ This sorting is done to get a device
+ order compatible with older (<= 2.4) kernels.
+ nobfsort Don't sort PCI devices into breadth-first order.
pcmv= [HW,PCMCIA] BadgePAD 4
Param: "schedule" - profile schedule points.
Param: <number> - step/bucket size as a power of 2 for
statistical time based profiling.
+ Param: "sleep" - profile D-state sleeping (millisecs)
processor.max_cstate= [HW,ACPI]
Limit processor to maximum C-state
pt. [PARIDE]
See Documentation/paride.txt.
- quiet= [KNL] Disable log messages
+ quiet [KNL] Disable most log messages
r128= [HW,DRM]
rcu.qlowmark= [KNL,BOOT] Set threshold of queued
RCU callbacks below which batch limiting is re-enabled.
- rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
- RCU callbacks to queued before forcing reschedule
- on all cpus.
-
rdinit= [KNL]
Format: <full_path>
Run specified binary instead of /init from the ramdisk,
reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Format: <reboot_mode>[,<reboot_mode2>[,...]]
- See arch/*/kernel/reboot.c.
+ See arch/*/kernel/reboot.c or arch/*/kernel/process.c
reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
+ reservetop= [IA-32]
+ Format: nn[KMG]
+ Reserves a hole at the top of the kernel virtual
+ address space.
+
+ reset_devices [KNL] Force drivers to reset the underlying device
+ during initialization.
+
resume= [SWSUSP]
Specify the partition device for software suspend
+ resume_offset= [SWSUSP]
+ Specify the offset from the beginning of the partition
+ given by "resume=" at which the swap header is located,
+ in <PAGE_SIZE> units (needed only for swap files).
+ See Documentation/power/swsusp-and-swap-files.txt
+
rhash_entries= [KNL,NET]
Set number of hash buckets for route cache
scsi_logging= [SCSI]
+ scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
+ discovered. async scans them in kernel threads,
+ allowing boot to proceed. none ignores them, expecting
+ user space to do the scan.
+
selinux [SELINUX] Disable or enable SELinux at boot time.
Format: { "0" | "1" }
See security/selinux/Kconfig help text.
sg_def_reserved_size= [SCSI]
- sgalaxy= [HW,OSS]
- Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
-
shapers= [NET]
Maximal number of shapers.
snd-ymfpci= [HW,ALSA]
- sonicvibes= [HW,OSS]
- Format: <reverb>
-
sonycd535= [HW,CD]
Format: <io>[,<irq>]
sym53c416= [HW,SCSI]
See header of drivers/scsi/sym53c416.c.
+ sysrq_always_enabled
+ [KNL]
+ Ignore sysrq setting - this boot parameter will
+ neutralize any effect of /proc/sys/kernel/sysrq.
+ Useful for debugging.
+
t128= [HW,SCSI]
See header of drivers/scsi/t128.c.
uart6850= [HW,OSS]
Format: <io>,<irq>
+ uhci-hcd.ignore_oc=
+ [USB] Ignore overcurrent events (default N).
+ Some badly-designed motherboards generate lots of
+ bogus events, for ports that aren't wired to
+ anything. Set this parameter to avoid log spamming.
+ Note that genuine overcurrent events won't be
+ reported either.
+
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.
norandmaps Don't use address space randomization
Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
+ unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
+ This is useful to get more information why
+ you got a "dwarf2 unwinder stuck"
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